1. Field of the Invention
The present invention is directed to a hand-held epilating device, and more particularly to such a device having a rotary cylinder carrying a plurality of hair pinching rows arranged around an axis of the rotary cylinder.
2. Description of the Prior Art
U.S. Pat. No. 5,190,559 discloses a prior art epilating device which has a rotary cylinder carrying a pair of hair pinching rows spaced circumferentially around the rotary cylinder. Each of the pinching rows includes a plurality of stationary blades and a plurality of movable blades which are arranged along the lengthwise direction of the rotary cylinder with the tow adjacent movable blades disposed on opposites of each stationary blade. The movable blades in each pinching row are supported to a pair of actuator bars which are driven to counter-reciprocate along the longitudinal axis of the rotary cylinder in order to shift the movable blades towards the adjacent stationary blades for pinching the body hairs between the blades. Subsequently, the pinched hairs are plucked from a user""s skin as the rotary cylinder rotates. In order to catch the hairs between the blades as well as to release the plucked hairs, the actuator bars in each pinching row is urged by a return spring to move the movable blades away from the adjacent stationary bars prior to and subsequent to pinching the hairs. The spring is required between the counter-reciprocating actuator bars in each pinching row. That is, each pinching row necessitates one return spring. Consequently, as the number of the pinching rows increases, a correspondingly increased number of the springs have to be incorporated in the rotary cylinder, which incurs difficulty of assembling the increased number of the springs into the rotary cylinder. Therefore, it has not been practical to provide a large number of the pinching rows yet using the return springs for each of the pinching rows.
The present invention has been accomplished in view of the above insufficiency to provide an improved epilating device which is capable of realizing an increased number of the pinching rows around a rotary cylinder with a minimum number of return springs. The epilating device in accordance with the present invention includes a housing to be grasped by a hand of a user, and a rotary cylinder mounted to the housing and having a longitudinal axis. The rotary cylinder carries a plurality of pinching row units which are circumferentially spaced about the longitudinal axis. Each pinching row units includes at least one set of blades arranged along the longitudinal axis of the cylinder. Also included in the rotary cylinder are a plurality of actuator bars which are arranged circumferentially about the longitudinal axis and are associated with the pinching rows, respectively. Each of the actuator bars extends through the rotary cylinder and is driven to shift along the longitudinal axis. Each actuator is connected to move at least one of the blades in each pinching row unit against and away from the adjacent stationary blade for catching and pinching the body hairs therebetween. A drive mechanism is provided for driving the actuator bars to reciprocate along longitudinal axis while rotating the rotary cylinder about the longitudinal axis for pinching the body hairs between the adjacent blades and plucking the hairs from the user""s skin. The distinguishing feature of the present invention resides in that all the circumferentially spaced actuator bars are coupled commonly to a single return spring so as to be urged thereby in a direction of moving the blades away from the adjacent blade. Accordingly, an increased number of the pinching rows can be realized around the rotary cylinder only with the use of a minimum number of the return spring.
It is therefore a primary object of the present invention to provide the epilating device which is capable of achieving efficient hair plucking due to the increased number of the pinching row units around the rotary cylinder, yet ensuring to moving the movable blades away from the adjacent stationary blades by the use of the return spring for successfully catching the hairs with increased hair trapping efficiency.
In a preferred embodiment, the return spring includes a plurality of spring arms extending radially from a center hub secured to the rotary cylinder. Each spring arm is held in pressing engagement simultaneously with the circumferentially adjacent actuator bars for urging the bars axially outwardly of the rotary cylinder. Thus, the number of the spring arms can be half that of the circumferentially arranged pinching units, thereby simplifying the structure of the return spring.
The spring arm is U-shaped to have a first radial segment extending from the hub and a second radial segment which extends from the outer radial end of said first radial segment through an arc segment and projects radially inwardly from the arc segment. The second radial segment is utilized to be held in pressing engagement commonly with the two circumferentially adjacent actuator bars. With this U-shaped configuration, the second radial segment can be given an effective spring length which is sufficiently long relative to a radial dimension of the return spring, thereby giving a sufficient biasing force for moving the blade away from the adjacent blade only at a minimum radial dimension of the return spring.
In order to further increase the spring force, the spring arms are shaped to extend in a spiral fashion from the center hub about an axis of the hub. The hub may be formed with a hole which receives a portion of the rotary cylinder for fixedly mounting the return spring to the rotary shaft as well as for allowing an axle to pass therethrough for supporting the rotary cylinder to the housing.
Each of the actuator bars has a first end coupled to at least one blade in each set of blades and has a second end projecting on one longitudinal end face of the rotary cylinder in an opposing relation to a cam roller which is included in the drive mechanism. The cam roller is positioned to be in selective contact with the second ends of the actuator bars in such a manner as to move the actuator bars in a direction of pinching the body hairs between the blades as the rotary cylinder rotates about the longitudinal axis. The second end of each actuator bar is shaped to extend circumferentially about the longitudinal axis give an arcuate flange. The arcuate flanges of the circumferentially adjacent actuator bars are partially overlapped with each other in a radial direction of the rotary cylinder such that the overlapped portions of the arcuate flanges come simultaneously into contact with the cam roller. In this connection, each spring arm of the return spring is engaged with the radially overlapped portions of the arcuate flanges of the two circumferentially adjacent actuator bars. With this arrangement, the arcuate flanges of the adjacent actuator bars come into simultaneous contact with the cam roller to keep pinching the hairs over a prolonged period during which the cylinder continues rotating to pluck the hair successfully. Therefore, it is possible to arrange an increased number of the pinching rows around the rotary cylinder of a limited diameter, yet assuring to make the hair plucking successfully.
It is preferred that each of said arcuate flanges is formed at its opposite ends with receding slant faces away from the cam roller in order to reduce an impact when the actuator bars come into contact with the cam roller, thereby assuring smooth closing and opening movement of the blades and therefore reduced-in-noise operation.
In a preferred embodiment, each pinching row units includes a plurality of stationary blades and a corresponding number of movable blades which are arranged alternately in a direction parallel to said longitudinal axis. An advantageous feature associated with this embodiment resides in that the two longitudinally adjacent stationary blades in each of said pinching row units are integrally shaped from the same metal into a single integrated piece in which the two adjacent stationary blades are inseparably continuous with each other, and that the integrated piece is associated with the two adjacent movable blades which are connected commonly to one of the actuator bars and are caused thereby to move simultaneously against and away from the stationary blades of the integrated piece. With the use of the integrated piece, the two metal-made stationary blades can be positioned accurately or have precise dimensional relationship with each other, thereby been given uniform pinching effects with the associated movable blades driven to move simultaneously by a single actuator bar. Thus, it is easy to eliminate undesired variation in the hair pinching effects between the stationary blades and therefore to assure consistent and effective hair plucking.
Preferably, the two movable blades associated with the integrated piece are pivotally supported to a holder plate so as to be pivotable about a pivot axis perpendicular to the longitudinal axis of the rotary cylinder for movement against and away from the associated stationary blades. The holder plate mounts at least one integrated piece and the associated movable blades and consolidating these members together into a self-sustained sub-assembly which is fitted on the surface of said rotary cylinder. Thus, the pinching row units can be easily assembled to the rotary cylinder for increasing manufacturing efficiency.
The holder plates also mounts a skin guide which is disposed between the two adjacent stationary blades of the integrated piece and has an arcuate surface for smooth contact with the skin of the user""s body. The skin guide is consolidated into the sub-assembly and has a grip which fixes the integrated piece to the holder plate in a correct position relative to the corresponding movable blades. The skin guide can be molded from a plastic material so as to be easy to be press-fitted to the holder plate, and is therefore best utilized to unite the metal-made integrated piece, i.e., the stationary blades to the holder.
The two adjacent stationary blades are interconnected by a pair of beams extending in the direction of the longitudinal axis and merging at opposite lengthwise ends into lower ends of the stationary blades. Formed at the connection between the beams and the stationary blades are resilient segments which are responsible for absorbing a stress applied to the stationary blade from the associated movable blade. Thus, excessive force applied to one of the stationary blade from the movable blade can be well absorbed at the resilient segments, which making it easy to balance the pinching forces at the two stationary blades for uniform plucking of the hairs.
The arcuate surface of the skin guide is formed at its one end with a rounded edge which is continuous with a remainder of the arcuate surface and has a curvature greater than that of the remainder of the arcuate surface. The rounded edge of increased curvature can well prevent the skin from being irritated when the skin guide comes firstly into contact with the skin as a consequence of the rotary cylinder rotates, thereby assuring comfortable hair plucking.
Each of the stationary blade and the corresponding movable blade may be formed at its one lengthwise facing toward a rotating direction of said rotary cylinder with a flared edge. The flared edges are cooperative with each other to define therebetween a tapered groove for smoothly guiding the hairs into between the blades.
In the preferred embodiment, the two integrated pieces are mounted to the one holder plate to constitute the sub-assembly in which the four stationary blades are evenly spaced along the longitudinal axis of the rotary cylinder. The rotary cylinder carries a plurality of the sub-assemblies which are circumferentially spaced about the longitudinal axis with the sub-assemblies being staggered with each other with respect to the longitudinal axis, in order to increase chances of the hair plucking within the length of the rotary cylinder. For maximum efficiency of plucking the hairs per length of the rotary cylinder, all the stationary blades of different rows are offset from each other with respect to the longitudinal axis of the cylinder.
These and still other objects and advantageous features of the present invention will become more apparent from the following description of the preferred embodiment when taken in conjunction with the attached drawings.